Bison,
We've worked in the past with the JoomlaXi folks to help with integration between JFBConnect and JSPT. However, we haven't tested their newer releases and I can't guarantee there won't be issues.
JFBConnect, in general, creates 100% standard users which any other extension sees just like normal. In the past, JSPT has had issues with getting the user's profile information during the registration process. Once the user is logged in though, they can edit their JSPT profile just like normal. So, it depends on exactly how you're planning on integrating, and the questions may have to be directed to JSPT developers as they know more about how they've managed the integration.
Finally, as always, we have a 30-day money back guarantee. Should you subscribe to JFBConnect and can't get things going how you like, you can easily obtain a refund.
Hope that helps,
Alex